An advertisement in The Moving Picture World, February 28, 1914, stated that his initial Thanhouser role was in Their Best Friend, released on February 27th. For the New Rochelle studio he acted in many productions, including Richelieu, Deborah, Gods Witness, The Bubbles in the Glass, In the Name of the Law, and Through the Enemys Lines, to cite a few which he in later years considered to be memorable.
A 1914 biographical sketch noted: “Since being with the Thanhouser company, Mr. Foster estimates that he has stolen 57 varieties of wives from their husbands—on the screen, of course.” New Rochelle directories indicate that in 1914 he lived at the Pepperday Inn, less than a block away from the Thanhouser studio, and in 1915 in Beacon Hall, an apartment building next to the studio. In April 1915 he married Mignon Anderson, one of the leading ladies at the Thanhouser studio. The couple honeymooned in Jacksonville, Florida, and reported back to work at the studio on Monday, April 26th. Their marriage was a love match, and the couple remained close until Fosters death.
Later, he went to Famous Players, where he appeared in The Innocent Lie (May 1916) and other films. Morris Foster was in several Gold Seal (Universal) releases in 1917, including The Young Patriot, The Storm Woman and The Taming of Lucy. In the 1918 edition of the Motion Picture Studio Directory his mailing address was given as the Friars Club, New York City. In 1919 he was in the Paramount release of You Never Saw Such a Girl. He appeared in many other productions through 1920. A contemporary description noted that he was of medium complexion and had blue eyes. He considered himself an all-around athlete and enjoyed the hobby of raising fancy pigeons. J. Morris Foster died in Burbank, California on April 24, 1966. His ashes were deposited at the Forest Lawn Cemetery. He was survived by his widow, Mignon Anderson.